Field of the Invention
The present disclosure relates to a liquid crystal display apparatus, and more particularly, to a liquid crystal display apparatus which is capable of reducing assembly defects of the liquid crystal display apparatus by improving a bolting structure for assembling components, and realizing a thinner liquid crystal display apparatus. Also, by applying a pad unit composed of a foam pad layer and a rigid layer, a distance between the components can be secured and an impact of collision between the components can be relieved.
Description of the Related Art
A liquid crystal display apparatus is a display apparatus including a liquid crystal display panel. The liquid crystal display apparatus is driven by adjusting a transmittance of the liquid crystal display panel with respect to light from a light source such as a backlight unit. In recent years, a demand for a liquid crystal display apparatus with high resolution and low power consumption as well as a liquid crystal display apparatus with a reduced thickness and a minimized bezel has been increasing.
The liquid crystal display apparatus can be used as a part of an electronic device. If the liquid crystal display apparatus is used as a part of an electronic device, the liquid crystal display apparatus is configured to be connected with a housing of the electronic device and other components attached to the housing. For example, the liquid crystal display apparatus may be used as a part of a monitor or a television and may be connected with a housing of the monitor or television.
Meanwhile, the components of the liquid crystal display apparatus are accurately fixed at positions as designed, so that a minimum distance therebetween can be secured. If the components are not accurately fixed at positions as designed and thus a minimum distance therebetween cannot be secured, the components may be brought into undesired contact with each other or another component may be located at a position of one component, so that the liquid crystal display apparatus may be difficult to assemble.
A liquid crystal display apparatus of the related art includes a cover unit configured to partially surround an end of a liquid crystal display panel and a chassis for protecting the liquid crystal display panel. A flexible printed circuit board configured to connect a circuit unit for driving the liquid crystal display panel with the liquid crystal display panel is protected by the cover unit. The cover unit has large thickness in order to protect a part of the liquid crystal display panel and is fixed to a lateral side of the chassis. Further, the cover unit is disposed not to be in contact with the flexible printed circuit board.
Meanwhile, in order to realize a thin liquid crystal display apparatus, a structure not requiring a cover unit may be used. In this structure, a separate thin shield unit for protecting a flexible printed circuit board and a circuit unit may be used instead of the cover unit. The shield unit has small thickness and has a minimum distance from the other components in order to realize a thin liquid crystal display apparatus. In particular, the shield unit is configured to be in contact with the flexible printed circuit board. If the shield unit is in contact with the flexible printed circuit board and has a small distance from the other components and thus cannot be accurately fixed at a position as designed, when the components of the liquid crystal display apparatus are connected with each other, the components may be overlapped in position. Also, a shied unit-fixing structure such as a screw may be used in order to accurately fix the shield unit at a position as designed. However, a pressure applied to the liquid crystal display apparatus when the fixing structure is connected with the liquid crystal display apparatus may cause a change in a distance between the components of the liquid crystal display apparatus, and, thus, the components may be damaged.
In this regard, the liquid crystal display apparatus includes the chassis for accommodating the liquid crystal display panel. The chassis is configured to protect the liquid crystal display panel and also fix a position of the backlight unit or the like. In order to suppress a foreign material from being introduced between the chassis or between the chassis and another component into the liquid crystal display apparatus from the outside, a pad unit formed of a silicon material is provided between the chassis or between the chassis and another component.
Meanwhile, in order to make a liquid crystal display apparatus thin and minimize or remove a bezel, a distance between the chassis and the components disposed inside the chassis has been decreasing more and more. As a distance between the components is decreased, some of the components may be overlapped in position when the liquid crystal display apparatus is assembled. In addition, if a force is applied to the fixing structure in order to fix the shield unit, the components apply a pressure to each other, thereby causing damage to the components and various problems may occur.
In the related art, a pad unit is disposed between the liquid crystal display panel and a lateral chassis connected with the liquid crystal display panel in order to suppress a foreign material from being introduced, which causes various problems such as a short circuit. In the related art, the pad unit was formed of silicon having fixed thickness. Thus, if the pad unit is too thick, when the liquid crystal display panel and the lateral chassis are assembled, the pad unit applies a pressure to the liquid crystal display panel, and, thus, for example, alignment of a liquid crystal may be changed. If alignment of the liquid crystal is changed, a light-leakage phenomenon may occur in the liquid crystal display panel, resulting in a decrease in visibility.
However, the liquid crystal display apparatus of the related art uses an opaque cover unit. Therefore, even if a light-leakage phenomenon occurs in the liquid crystal display panel, an edge portion of the liquid crystal display panel is hidden by the cover unit and the light-leakage phenomenon is actually invisible to the naked eye.
As such, the cover unit may be used to hide light leakage occurring at the edge portion. However, in recent years, there is a tendency not to use the cover unit in order to further reduce thickness of the liquid crystal display apparatus. However, if a pad unit formed of silicon is used in a structure without using the cover unit, a pressure is applied to the liquid crystal display panel, and, thus, light leakage caused by a change in alignment of the liquid crystal may be directly exposed to a user. Further, if a pad unit having small thickness is used to minimize an overlap in position between the liquid crystal display panel and the pad unit, a foreign material from the outside may not be blocked.
Further, a light guide plate is disposed on a lower chassis for covering a lower side of the liquid crystal display apparatus, and a reflector is disposed under the light guide plate. At an edge portion of the reflector, an ink portion printed with black ink is formed in order to minimize reflection of light from the backlight unit in an undesired direction at the edge portion of the reflector. The ink portion reduces light leakage caused by the reflector.
Meanwhile, a pad unit is also disposed between the lower chassis and the lateral chassis. The pad unit seals a space between the lower chassis and the lateral chassis. Further, the pad unit separates the lower chassis from the reflector and the lower chassis from the light guide plate. However, when the lateral chassis and the lower chassis are connected with each other with the pad unit therebetween, if a sufficient distance between the lateral chassis and the lower chassis is not maintained, the pad unit bonded to a protruding portion of the lateral chassis may press an edge portion of the light guide plate. If pressure and heat are applied to the pressed edge portion of the light guide plate, the ink portion adheres to the light guide plate. When the reflector made of metal is expanded under a high-temperature and high-humidity condition, since the ink portion adheres to the light guide plate, the reflector cannot be evenly expanded but may be expanded with wrinkles. Such a phenomenon is referred to as a wrinkling phenomenon. The reflector in which the wrinkling phenomenon occurs cannot uniformly reflect an incident light throughout the liquid crystal display panel, and the non-uniformly reflected light may be seen as a mura.